42 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
the east and west have an elevation of between 4,500 and 5,000 feet. 
When seen from the Sevier desert on the east, the crest of the southern 
part of the range shows some rather strong knobs, from which it has 
been called the Sawtooth range; this name will here be used for the 
quarter of its length that lies south of the southern of the two roads 
by which it is crossed. The next quarter, rather a short quarter, 
Fie. 18.— East-west section of the Swazy mass, looking north: length of sec- 
tion, about 5 miles, 
indeed, lies between the two roads; it has an even crest and a sim- 
pler back slope than the rest of the range; this part will therefore 
here be designated by a provisional name, the Smoothback mass, 
because of its freedom from deep ravines by which the eastern slope 
of the range is elsewhere dissected. Then comes the Swazy mass, 
north of which our excursion did not reach. The parts of the 
Fic. 19.— The south end of the Smoothback escarpment, showing the notch by 
which the southern road ascends to the oblique transverse depression that is 
worn on the Trilobite shales; looking east. 
range here referred to are shown on the rude map of figure 17. 
The lowest beds that we saw along the base of the western escarp- 
ment were chiefly dull reddish quartzitic strata, several hundred feet 
in thickness; these were followed by a great body of limestones with 
some shales near their middle; the lower limestones make gray-and- 
